What exactly are you going to do? Ring his doorbell and punch him in the face? Holding someone personally responsible over the internet is rather ....pointless.
Holding him responsible over the Internet weakens any post he makes in the future if he doesn't come through with his promises like he has failed in the past. Part of who he is on the Internet is important to him. If he continues to make empty promises he will lose that.
I'm sorry you haven't grasped this most simple princeple. Perhaps you should log off now.
Perhaps you should take a class in Internet communication. I feel that would be best for you.